21.Select the correct statement

22.A disc of mass 4 kg, radius 0.5m and moment of inertia 3 kg-m2 rolls on a horizontal surface so that its centre moves with speed 5 m/see. Kinetic energy of the disc is

23.If a projectile is fired with an initial velocity of 10 m/sec at an angle of 60� to the horizontal, its horizontal and vertical velocity at the highest point of trajectory are

24.The angle of projection at which the horizontal range and maximum height of a projectile are equal to